Magnetic resonance imaging (MRI) techniques are widely used in clinical examinations and medical diagnoses in recent years. For example, an MRI scanner may perform a scan on a subject located within its detection region and generate magnetic resonance (MR) signals relating to the subject. A phase image may be generated by extracting phase information from the MR signals. In general, the phase image can reflect multiple physical information, for example, a distribution of a magnetic field, the current state of an MRI system, etc. In some embodiments, the phase image may be generated based on, for example, an inverse trigonometric function. Accordingly, the phase information may be limited within a range of 2π, for example, (−π, π], (0, 2π], etc. If an actual phase exceeds this range, the actual phase may be wrapped into the range, which is called “phase wrapping.” A phase image generated according to the wrapped phase information may have a wrapping artifact. Thus, it is desirable to reduce or eliminate phase wrapping in a phase image to improve the quality of the phase image.